In manual processes for cutting a workpiece along a cutting line, the operator has to approach the end points of the cutting line by manually controlling the motor-driven advancing mechanism during the processing. If the saw blade is surrounded by a blade guard, the exit points of the saw blade in the workpiece are hardly or not at all visible to the operator, so that the operator cannot determine the end points of a cutting line during the work process.
European patent application EP 1 693 173 A1 discloses a method that is at least partially automated for controlling a device system during the cutting of a workpiece along a cutting line. The device system consists of a guide rail, a saw head that is arranged so as to be movable on the guide rail and a motor-driven advancing mechanism to move the saw head along the guide rail. The saw head comprises a saw blade that is attached to a saw arm and that is driven around a rotational axis. The saw arm is configured so that it can be swiveled around a swivel axis. The cutting depth of the saw blade in the workpiece is varied by a swiveling movement of the saw arm around the swivel axis. The saw blade is rotated around the rotational axis by a drive motor, while the saw arm is swiveled by a swivel motor. The drive motor and the swivel motor are arranged in a device housing of the saw head. The motor-driven advancing mechanism comprises a guide carriage and an advancing motor that is arranged in the device housing. The saw head is installed on the guide carriage and configured so as to be movable by the advancing motor along the guide rail in an advancing direction. Aside from the motors, there is also a control unit that is installed in the device housing and that serves to control the wall saw and the motor-driven advancing mechanism.
This prior-art method for controlling the device system during the cutting of a workpiece entails a sequence of three method steps that are carried out one after the other. In the first method step, the saw arm is slanted at a swivel angle that corresponds to the depth of the partial cut. In the second method step, the saw head is moved forward along the guide rail along the advancing direction until it reaches the first end point of the cutting line. In the third method step, the saw head is moved backwards along the guide rail along the advancing direction until it reaches the second end point of the cutting line. These three method steps are continuously repeated until the desired cutting depth has been reached. The at least partially automated cutting method requires the operator to enter the end points of the cutting line but it does not contain any information about how the coordinates of the end points are specified by the operator.